Ron Cooper is an old army veteran with enough illegal weapons, ammunition and explosives to run his own militia. He gets injured when a rifle backfires and is taken to hospital. Unknown to him four boys have found his collection and they "borrow" a box of ammunition not knowing how dangerous it is. Furthermore Greengrass buys some hand grenades from Cooper's helper Morris and cleans out lord Ashfordly's entire stock of trout. Meanwhile Kate Rowan's work at Radcliffe's surgery in Whitby is taking its toll on their marriage and they start to drift apart, when Kate discovers that she is pregnant.

Aidensfield is in a fever of excitement when Nick and Kate return with their beautiful new-born baby girl and everybody showers them with presents. Only nobody else in the village knows that Kate is dying of leukaemia, and Nick tries to spend as much time with her and the baby as possible. He is even neglecting his job as police constable. That leads to several complaints against him because a thief is stealing petrol from cars in the village at night. Not even sergeant Blaketon's police car escapes the thief.

PC Ventress has bought a building plot and wants to build a new home for him and Mrs. Ventress. He has hired Claude Greengrass and David Stockwell to do the digging at the plot. Suddenly they come across a 500 kg highly explosive leftover from World War II. And Greengrass gets trapped right alongside it. PC Rowan starts to evacuate the village while they wait for the bomb squad to dispose of it. To top it all little Colin Ellis has disappeared and is nowhere to be found when the school children and other villagers have been evacuated. During the search for him the police find a dead body at station master Hutton's house. Suddenly the bomb starts ticking!

PC Rowan responses to an anonymous emergency call and find archaeologist Professor Brigstocke dead in his library and the house broken into. The professor was said to hide a treasure and Greengrass decides to find it. Clues lead to the ruins of Saint Columba's Abbey on the Ashfordly estate. But also Mary Secker, who is writing a book on 12th century monasteries, is interested in the ruins. Lord Ashfordly is hosting a fishing party and is not pleased to find fishing net and no fish in his river. Blaketon suspects Greengrass is behind it and when the old scoundrel enters the abbey to look for the treasure, Blaketon is close behind him. They both get trapped and Blaketon breaks a leg when part of the ruins cave in, and Greengrass lights a fire to keep him warm.

Les Hepplewhite is the leader of a brass band. He has high hopes for the band to regain the Wallace Cup at the upcoming contest. The same has Bill Bugde the leader of a competing band. But there is more behind their enmity than just rivalry over a trophy and the police has to step in when several members of Hepplewhite's band end up in hospital with food poisoning. Dawn is completely swept off her feet by Jonny Leigh who pulls up at Bernie's garage for some petrol. He invites her to move with him to Paris, but the other villagers think things are happening too fast and Aunt Peggy asks her to wait - at least until Gina returns from Liverpool where she has gone to see her family. The heat is on between Joe Mason and Rachel Dawson after he saved her career, but it takes its toll on the relationship between him and Carol Cassidy. Especially after Carol discovers that Rachel has spent a night with him at the police house.